Volume 13, No. 3, June 2013, Pages 932-942 PDF(1.25 MB)
Atmospheric Arsenic Deposition in Chiayi County in Southern Taiwan
Long-Full Lin1, Shu Hsien Wu2, Sheng-Lun Lin3,4, John Kennedy Mwangi2, Yi-Ming Lin5, Chia-Wei Lin2, Lin-Chi Wang4,6, Guo-Ping Chang-Chien4,7
1 Department of Environmental Engineering, Kun Shan University, Yung Kang, Tainan City 71003, Taiwan
2 Department of Environmental Engineering, National Cheng Kung University, Tainan City 70101, Taiwan
3 Center of General Education, Cheng Shiu University, Kaohsiung City 83347, Taiwan
4 Super Micro Mass Research and Technology Center, Cheng Shiu University, Kaohsiung City 83347, Taiwan
5 College of Environmental Science and Engineering, South China University of Technology, Guangzhou 510640, China
6 Department of Civil Engineering and Engineering Informatics, Cheng Shiu University, Kaohsiung City 83347, Taiwan
7 Department of Cosmetic and Fashion Styling, Cheng Shiu University, Kaohsiung City 83347, Taiwan
Although arsenic contamination of underground water in southern Taiwan is well known, few studies examine atmospheric arsenic deposition in this area, which might be the major source of such pollution to the soil, water, and even underground water. This research focused on the atmospheric arsenic concentration, dry and wet depositions, and the As distribution around Chiayi County, located in the south of Taiwan. Eight sampling sites are used, both upwind and downwind of an area with heavy industrial and human activities. All samples were collected by a PS-1 high volume sampler at each site, pretreated by a digestion process, and further analyzed with an ICP-MS. The results show that the arsenic deposition flux ranged from 65.0 to 473 μg/m2-month in Chiayi County. This deposition flux has no significant seasonal variation, based on the multiple trend results obtained from pooling the dry and wet deposition data. The average dry deposition flux of As ranged from 34 to 161 μg/m2-month during the sampling year, and had the opposite trend to the wind speed. Additionally, the correlations between atmospheric arsenic concentration and PM levels were significant, supported by the low p-value (< 0.01) at a 99% confidence level. Meanwhile, the highly linear correlation between As and PM concentrations was also evaluated. The amount of precipitation was statistically correlated to the wet deposition flux (11.3–414 μg/m2-month with a p-value = 2 × 10–7 and r-value = 0.9306. Furthermore, the composition of the As mass concentrations in ambient air were dominated by As (V) in both fall (66.4%) and winter (68.9%). According to the GIS spatial analysis of the As concentration in the dry season, from October to March, the As contribution of local emissions were not significant. Consequently, this study indicates that the atmospheric As around Chiayi County might be sourced from the upwind northern area, and mainly deposited through wet scavenging.
Arsenic; Dry deposition; Wet deposition.